An LED is a light generating semiconductor element that can be connected to a source of electricity. LEDs can generate light at a variety of wavelengths and levels of brightness with greater life, better durability, and higher energy efficiency than traditional lighting solutions. LEDs are increasingly being used in diverse applications including interior and outdoor lighting. For example, wall and ceiling mounted lights, floodlights, garage and parking lights, roadway lights, and landscape lighting have all incorporated LEDs.
LED lighting devices typically utilize a plurality of LEDs mounted on a surface, such as a printed circuit board. The LEDs may be in LED packages that contain a semiconductor chip which generates light and is embedded on a submount. The submount may include a heat sink and is typically surrounded by an outer housing. A primary lens extends from the housing and further encloses the semiconductor chip. Anode and cathode leads, pads, or terminals, may extend out of the housing to conduct electricity to the semiconductor chip. The LEDs and the printed circuit board are typically covered by a housing, which may provide protection against external elements. Various internal reflectors or lenses may be provided inside the housing for amplifying and directing light as needed.
For a number of applications, the voltage used to power the LEDs renders the device a non-Class 2 component as defined by NEC Article 725 which is incorporated herein by reference. Class 2 devices have a limit of 60 V peak voltage in the U.S. and 42.2 V peak voltage in Canada. If the voltage exceeds these levels, the devices are designated by the Underwriters Laboratories (UL) as a fire risk and must be contained in Class 1 compliant appropriate housing using only suitable materials.
Typical enclosures have utilized glass and/or metal housings that are secured to the circuit board and spaced apart from the LEDs. Such enclosures, however, can be, expensive, heavy, prone to break, and present additional risks to users. These enclosures may also negatively affect the amount of light that can be transmitted from the LED to the environment. To compensate for this deficiency, more LEDs must be used or the brightness of the LEDs must be increased, further increasing costs and reducing the energy efficiency of each lighting unit.